Alright, So I'm driving to work. I'm stopped at the red light to go on the freeway. It turns green so I accelerate. I'm accelerating more than I would on a regular street but I didn't floor it. Anyway, all of the sound my exhaust sounds REALLY loud. It sounds like I have no muffler or something. I pull in to a gas station but my muffler is still there. It's loud at idle and gets louder the more I push down on the pedal. The sound sounds like it's coming from under the driver's feet. I looked under the car where I think the noise is coming from and I don't really see anything. It looks like a bolt may be missing from about the same spot the noise is coming from but I don't know if it's related or just a coincidence. I don't remember hearing anything falling off my car when it happened. No warning lights or anything. Any ideas?

2 Answers
2

Probably a cracked/rusted out weld somewhere. Could be a hole that finally rusted through. Sometimes the bolted together joints rust through. Typically results in a cat-back exhaust replacement. Can end up being full system replacement. Rarely can be fixed in just one location.

Will it damage my car to drive it home (50 miles)?
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user990Sep 1 '11 at 14:12

Impossible to say for certain, especially without knowing the exact cause/location. Generally speaking, the risk of damage is low for this type of thing. Unfortunately, the modes of failure that you are exposed to (while not real likely) are pretty nasty (hot exhaust burning through something/setting something on fire, parts dropping from your car and jamming into the roadway causing control problems, parts falling off and hitting a car behind you, etc.). Also, there's the risk of getting an excessive noise traffic ticket to consider as well.
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Brian KnoblauchSep 1 '11 at 14:38

I agree, it is likely a hole in your exhaust. I have a 99 A4 and get an exhaust leak about once a year by the flex pipe near the front. If a CEL didn't come on, I couldn't imagine something mechanically wrong that would cause it. Easy way to check is to jack the car up or put it on a lift while running and see if you feel air being blown somewhere along the exhaust. DON'T TOUCH THE EXHAUST, it will burn you. Just run your hand 6-12inches away.